Light emitting apparatus and method for manufacturing the same

ABSTRACT

The purpose of the invention is to improve reliability of a light emitting apparatus comprising TFTs and organic light emitting elements. The light emitting apparatus according to the invention having thin film transistors and light emitting elements, comprises; a second inorganic insulation layer on a gate electrode, a first organic insulation layer on the second inorganic insulation layer, a third inorganic insulation layer on the first organic insulation layer, an anode layer formed on the third inorganic insulation layer, a second organic insulation layer overlapping with the end of the anode layer and having an inclination angle of 35 to 45 degrees, a fourth inorganic insulation layer formed on the upper surface and side surface of the second organic insulation layer and having an opening over the anode layer, an organic compound layer formed in contact with the anode layer and the fourth inorganic insulation layer and containing light emitting material, and a cathode layer formed in contact with the organic compound layer containing the light emitting material, wherein the third inorganic insulation layer and the fourth inorganic insulation layer are formed with silicon nitride or aluminum nitride.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a light emitting apparatus comprising alight emitting element which emits fluorescent light or phosphorescentlight. In particular, the invention relates to a light emittingapparatus comprising an active element such as insulation gate typetransistor or a TFT, and a light emitting element coupled thereto.

2. Description of the Related Art

A typical display apparatus utilizing liquid crystal uses a back lightor a front light for displaying images. A liquid crystal displayapparatus is employed as an image displaying unit in variouselectronics, but suffers a structural problem that it has a narrowangled field of view. On the contrary, a display which uses lightemitting elements providing electro-luminescence as a display unit has awider-angled field of view as well as high level of visual recognition.These advantages make the electro-luminescent display prospective forthe next generation.

A light emitting mechanism utilizing the electro-luminescence isconsidered as a phenomenon in which electrons injected from a cathodeand positive holes injected from an anode couple on a layer comprisinglight emitting material to form excitons and a Light is released whenthe excitons move back to the ground state. There are two types ofelectro-luminescence, i.e., fluorescent light and phosphorescent lighteach of which is considered as light emitted from the excitons in asinglet state (fluorescent light), and light emitted from the excitonsin a triplet state (phosphorescent light), respectively. The luminancefrom electro-luminescence ranges from thousands cd/m² to tens ofthousands cd/m², which makes it possible in principle to adopt theelectro-luminescence light emitting elements in a variety ofapplications including a display apparatus.

An example of a combination of a Thin Film Transistor (hereinafterreferred to as “TFT”) and a light emitting element is disclosed in theJapanese Patent Laid-Open No. JP-A-8-241047. In the constructiondisclosed in this JP-A-8-241047, an organic electro-luminescence layeris formed on a TFT comprising polycrystalline silicon, via an insulationfilm comprising silicon dioxide. A passivasion layer having a taperedend on the anode is positioned under the organic electro-luminescencelayer. The cathode is made from a material with a work function of 4 eVor less. An example of an applicable material is an alloy of metal suchas silver or aluminum, and magnesium.

Known methods for manufacturing the organic electro-luminescence layerinclude vacuum evaporation, printing, and spin coating. However, it isdifficult to form determined patterns on the organicelectro-luminescence layer by photolithography technique as used in thesemiconductor element manufacturing. In order to arrange the lightemitting elements in a matrix to make a display screen, a specialconstruction is necessary in which each pixel is partitioned withinsulation material, as disclosed in the above JP-A-8-241047.

In the first place, It was pointed out as a problem that an organiccompound used for the light emitting elements, and an alkali metal or analkali earth metal used for an electrode are degraded by reactions withwater and oxygen.

The organic light emitting element deteriorates due to following sixfactors, (1) change in the chemical characteristics of the organiccompound (2) fusion of the organic compounds by heat generated atoperating, (3) destruction of insulation due to macro-level defect, (4)deterioration of the interface between, the electrodes, or between theelectrode and the organic compound layer comprising the light emittingelement, (5) deterioration caused by instability in the amorphousstructure of organic compounds, and (6) irreversible destruction causedby stress or distortion due to the structure of the elements.

The deterioration by the factor (1) is caused by chemical changeincurred by excitation, or gas which are corrosive against the organiccompounds or moisture. The deterioration by the factor (2) and (3) iscaused by the operation of the organic light emitting element. Heat isinevitably generated when current flowing in the element is convertedinto Joule heat. When the organic compound has low melting point orglass transition temperature, the electric field concentrates aroundpinholes or cracks and dielectric breakdown occur. The deterioration bythe factors (4) and (5) is inevitable even when the element is stored atambient temperature. The deterioration by the factor (4) is known asdark spots, which are generated by the oxidation of the cathode or thereaction to moisture. For deterioration by the factor (5), all theorganic compounds used in the organic light emitting element areamorphous, so that they will be inevitably crystallized in a longperiod, and heat. Almost no organic compound can keep its amorphousstructure for a long time. For deterioration by the factor (6), a defectsuch as a crack or a break of the coating due to distortion may developby the difference in thermal expansion coefficient between components.Furthermore, the crack or the break may lead to a progressive defectsuch as dark spots.

The advance in sealing techniques has fairly mitigated the problem ofdark spots. However in practice, the deterioration is caused by two ormore of the above factors, which makes it difficult to take effectivepreventive measure. In typical sealing method, the organic lightemitting element formed over a substrate is sealed with sealant, anddrying agent such as barium oxide is applied in the spaces.Unfortunately, conventional preventive measures have failed to suppressthe deterioration of the light emitting apparatus to an acceptablelevel.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the above problems inorder to improve the reliability of a light emitting apparatuscomprising TFTs and organic light emitting elements.

For this purpose, according to the present invention, a light emittingapparatus with pixels consisting of electrically connected TFTs andlight emitting elements has a construction wherein the light emittingelements are formed by laminating an anode layer, a cathode layer, andan interposed layer containing light emitting material, surrounding theupper surface, the lower surface and the side surface of the lightemitting element with an inorganic insulation layer, and the anodelayer, the cathode layer and the layer containing light emittingmaterial respectively contact with the surrounding inorganic insulationlayer. The inorganic insulation layer is formed of silicon nitride oroxynitride of silicon such as a silicon nitride film or a siliconoxynitride film, or, nitride or oxynitride of aluminum such as aluminumnitride or aluminum oxynitride. More preferably, the silicon nitridefilm formed by radio frequency sputtering (RF sputtering) with frequencyranging from 13.56 MHz to 120 MHz and having silicon as a target isapplied.

The silicon nitride film manufactured by the RF sputtering has improvedeffect of blocking the external impurities and an effect of suppressingthe deterioration of the light emitting element by satisfying one of thefollowing conditions; (1) a silicon nitride film with etching rate of 9nm/min or less (preferably, 0.5 to 3.5 nm/min or less), (2) hydrogenconcentration of 1×10²¹ atoms/cm³ or less (preferably 5×10²⁰ atoms/cm³or less), (3) hydrogen concentration of 1×10²¹ atoms/cm³ or less(preferably 5×10²⁰ atoms/cm³ or less), and oxygen concentration from5×10¹⁸ to 5×10²¹ atoms/cm³ (preferably 1×10¹⁹ to 1×10²¹ atoms/cm³), (4)etching rate of 9 nm/min or less (preferably, 0.5 to 3.5 nm/min orless), and hydrogen concentration of 1×10²¹ atoms/cm³ or less(preferably 5×10²⁰ atoms/cm³ or less), or (5) etching rate of 9 nm/minor less (preferably, 0.5 to 3.5 nm/min or less), hydrogen concentrationof 1×10²¹ atoms/cm³ or less (preferably 5×10²⁰ atoms/cm³ or less), andoxygen concentration from 5×10¹⁸ to 5×10²¹ atoms/cm³ (preferably 1×10¹⁹to 1×10²¹ atoms/cm³).

In a construction where in a display screen has light emitting elementsarranged in matrix, the most preferable construction of an insulationlayer to partition the each pixel comprises a positive-type or anegative-type photosensitive organic resin material and has a curvatureradius of 0.2 to 2 μm or continuously varying curvature radiuses withinthe above range at the end of the patterns, and a tapered surface withan inclination angle from 10 to 75 degrees, preferably from 35 to 45degrees. The construction of a pixel in the light emitting apparatusaccording to the invention can mitigate the stress on the electrode endsof the pixel and suppress the deterioration of the light emittingelement, by forming an insulation layer which covers ends of theindividual electrode (either anode or cathode) of each pixel connectingto the TFT to partition each pixel, and by forming a layer containingthe light emitting material, and one of the anode layer or the cathodelayer, from over the pixel electrode to over the insulation layer.

The construction of a light emitting apparatus according to theinvention will be described below.

A light emitting apparatus comprising a TFT having a semiconductorlayer, a gate insulation film and a gate electrode, and a light emittingelement having an organic compound layer containing light emittingmaterial between a cathode layer and an anode layer, comprises,

a second inorganic insulation layer on the gate electrode,

a first organic insulation layer on the second inorganic insulationlayer,

a third inorganic insulation layer on the first organic insulationlayer,

an anode layer on the third inorganic insulation layer,

a second organic insulation layer overlapping with the end of the anode,the second organic insulation layer having an inclination angle from 35to 45 degrees,

a fourth inorganic insulation layer formed on the upper surface and theside surface of the second organic insulation layer, the fourthinorganic insulation layer having an opening over an anode,

an organic compound layer formed in contact with the anode layer and thefourth inorganic insulation layer, the organic compound layer containingthe light emitting material, and

a cathode layer formed in contact with the organic compound layercontaining the light emitting material,

wherein;

the third inorganic insulation layer and the fourth inorganic insulationlayer comprise silicon nitride or aluminum nitride.

A light emitting apparatus comprising a pixel section having a TFThaving a semiconductor layer, a gate insulation film and a gateelectrode, and a light emitting element including an organic compoundlayer containing light emitting material between an anode layer and acathode layer, and a driving circuit section formed with a TFT having asemiconductor layer, a gate insulation film and a gate electrode, thedriving circuit section being formed in the peripheral region of thepixel section, comprising;

a first inorganic insulation layer under the semiconductor layer,

a second inorganic insulation layer on the gate electrode, a firstorganic insulation layer on the second inorganic insulation layer,

a third inorganic insulation layer on the first organic insulationlayer,

an anode layer formed on the third inorganic insulation layer,

a second organic insulation layer overlapping with the end of the anodelayer, the second organic insulation layer having an inclination anglefrom 35 to 45 degrees,

a fourth inorganic insulation layer formed on the upper surface and theside surface of the second organic insulation layer, the fourthinorganic insulation layer having an opening over the anode layer,

an organic compound layer formed in contact with the anode layer and thefourth inorganic insulation layer, the organic compound layer containingthe light emitting material, and

a cathode layer formed in contact with the organic compound layercontaining the light emitting material,

wherein;

the third inorganic insulation layer and the fourth inorganic insulationlayer comprise silicon nitride or aluminum nitride,

seal patterns are formed on the fourth inorganic insulation layer, and

some or all of the seal patterns overlap with the driving circuitsection.

The cathode layer may have the fifth inorganic insulation layer thereon,which is formed with nitride of silicon or aluminum.

The third to the fifth inorganic insulation layers have the abovementioned etching characteristics, and hydrogen concentration and oxygenconcentration in the above range. By reducing the density of N—H bond,Si—H bond and the Si—O bond, the construction according to the inventioncan improve thermal stability of a film and make a fine film.

A light emitting apparatus comprising a pixel section having a TFThaving a semiconductor layer, a gate insulation film and a gateelectrode, and a light emitting element including an organic compoundlayer containing light emitting material between an anode layer and acathode layer, and a driving circuit section formed with a TFT having asemiconductor layer, a gate insulation film and a gate electrode, thedriving circuit section being formed in the peripheral region of thepixel section, wherein;

a barrier layer formed from an organic insulation layer on the pixelsection extends over the driving circuit section,

an inorganic insulation layer comprising silicon nitride or aluminumnitride is formed on the upper surface and the side surface of thebarrier layer,

seal patterns are formed over the inorganic insulation layer,

some or all of the seal patterns overlap with the driving circuitsection, and

a connection between the cathode layer and the wiring formed under theanode layer is provided inside of the seal patterns.

A light emitting apparatus comprising a pixel section having a first TFThaving a semiconductor layer, a gate insulation film and a gateelectrode, and a light emitting element including an organic compoundlayer containing light emitting material between an anode layer and acathode layer, and a driving circuit section formed with a second TFThaving a semiconductor layer, a gate insulation film and a gateelectrode, the driving circuit section being formed in the peripheralregion of the pixel section, wherein;

a barrier layer formed from an organic insulation layer on the pixelsection extends over the driving circuit section,

an inorganic insulation layer comprising silicon nitride or aluminumnitride is formed on the upper surface and the side surface of thebarrier layer,

seal patterns are formed the inorganic insulation layer,

the first TFT is formed inside of the seal patterns,

all or some of the second TFT overlap with the seal patterns, and,

a connection between the anode layer and the wiring formed under theanode layer is provided inside of the seal patterns.

The inorganic insulation layer comprises silicon nitride manufactured bythe RF sputtering method, and has the above mentioned etchingcharacteristics, and hydrogen concentration and oxygen concentration inthe above range.

Another aspect of the invention provides a method to manufacture thelight emitting apparatus, as described below.

A method for manufacturing a light emitting apparatus comprising a pixelsection having a TFT having a semiconductor layer, a gate insulationfilm and a gate electrode, and a light emitting element including anorganic compound layer containing light emitting material between ananode layer and a cathode layer, and a driving circuit section formedwith a TFT having a semiconductor layer, a gate insulation film and agate electrode, the driving circuit section being formed in theperipheral region of the pixel section, comprising steps of;

forming a first inorganic insulation layer on a substrate,

forming a semiconductor layer comprising crystalline silicon on thefirst inorganic insulation layer,

forming a gate insulation film on the semiconductor layer and a gateelectrode on the gate insulation film, and, forming an impurity regionof one conductive type and another impurity region of complementaryconductive type in the semiconductor layer,

forming a second inorganic insulation layer on the gate electrode,

forming a first organic insulation layer on the second inorganicinsulation layer,

forming a third inorganic insulation layer on the second organicinsulation layer,

forming an anode layer in contact with the third inorganic insulationlayer,

forming a second organic insulation layer overlapping with the end ofthe anode layer, the second organic insulation layer having aninclination angle from 35 to 45 degrees,

forming a fourth inorganic insulation layer on the upper surface and theside surface of the second organic insulation layer, the fourthinorganic insulation layer having an opening over the anode layer,

forming an organic compound layer containing the light emitting materialin contact with the anode layer, the organic compound layer having anend overlapping with the fourth inorganic insulation layer, and,

forming a cathode layer in contact with the organic compound layercontaining the light emitting material, wherein,

the third inorganic insulation layer and the fourth inorganic insulationlayer comprise silicon nitride or aluminum nitride formed by the RFsputtering.

Further, another construction of a method for manufacturing a lightemitting apparatus comprising a pixel section having a TFT having asemiconductor layer, a gate insulation film and a gate electrode, and alight emitting element including an organic compound layer containinglight emitting material between an anode layer and a cathode layer, anda driving circuit section formed with a TFT having a semiconductorlayer, a gate insulation film and a gate electrode, the driving circuitsection being formed in the peripheral region of the pixel section,comprising steps of;

forming a first inorganic insulation layer on a substrate,

forming a semiconductor layer comprising crystalline silicon on thefirst inorganic insulation layer,

forming a gate insulation film and a gate electrode on the semiconductorlayer, and, forming an impurity region of one conductive type andanother impurity region of complementary conductive type in thesemiconductor layer,

forming a second inorganic insulation layer on the gate electrode,

forming a first organic insulation layer on the second inorganicinsulation layer,

forming a third inorganic insulation layer on the second organicinsulation layer,

forming an anode layer in contact with the third inorganic insulationlayer,

forming a second organic insulation layer overlapping with the end ofthe wiring layer, the second organic insulation layer having aninclination angle from 35 to 45 degrees,

forming a fourth inorganic insulation layer on the upper surface and theside surface of the second organic insulation layer, the fourthinorganic insulation layer having an opening over the anode layer,

forming an organic compound layer containing the light emitting materialin contact with the anode layer, the organic compound layer having anend overlapping with the fourth inorganic insulation layer,

forming a cathode layer in contact with the organic compound layercontaining the light emitting material,

forming seal patterns on the fourth insulation layer at a position inwhich some or all of the seal patterns overlap with the driving circuitsection, and,

adhering a sealing plate in alignment with the seal patterns, wherein,

the third inorganic insulation layer and the fourth inorganic insulationlayer comprise silicon nitride or aluminum nitride formed by the RFsputtering.

In the above construction according to the invention, the third and thefourth inorganic insulation layers comprise silicon nitride by the RFsputtering method using only nitrogen as sputtering gas and havingsilicon as a target. The third inorganic insulation layer is formedafter formation of the first organic insulation layer, by heating anddehydrating under reduced pressure, while the reduced pressure ismaintained. The fourth inorganic insulation layer is formed afterformation of the second organic insulation layer, by heating anddehydrating under reduced pressure, while the reduced pressure ismaintained.

The light emitting apparatus herein refers to the apparatus which useselectro-luminescence for emitting light, in general. The light emittingapparatus includes a TFT substrate in which circuitry is formed with TFTon a substrate for light emission, an EL panel which incorporates thelight emitting elements formed with electro-luminescence material on aTFT substrate, and an EL module which incorporates external circuitryinto an EL panel. The light emitting apparatus according to theinvention can be incorporated in a variety of electronics such as amobile telephone, a personal computer and a television receiver.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view which illustrates the construction ofthe light emitting apparatus according to the invention.

FIG. 2 is a top view which illustrates the construction of the pixelsection of the light emitting apparatus according to the invention.

FIG. 3 is a cross-sectional view which illustrates the construction ofthe pixel section of the light emitting apparatus according to theinvention.

FIG. 4 is another cross-sectional view which illustrates theconstruction of the pixel section of the light emitting apparatusaccording to the invention.

FIG. 5 is an outside view of a substrate comprising components of thelight emitting apparatus according to the invention.

FIG. 6 is a view which illustrates a substrate constituting a lightemitting apparatus formed on a mother glass, and its separation.

FIGS. 7A to 7C show a construction of the input terminal in the lightemitting apparatus according to the invention.

FIGS. 8A to 8D are cross-sectional views which illustrate manufacturingprocesses of the light emitting apparatus according to the invention.

FIGS. 9A to 9C are cross-sectional views which illustrate manufacturingprocesses of the light emitting apparatus according to the invention.

FIGS. 110A to 11C are cross-sectional views which illustratemanufacturing processes of the light emitting apparatus according to theinvention.

FIGS. 11A and 11B are cross-sectional views which illustratemanufacturing processes of the light emitting apparatus according to theinvention.

FIG. 12 is a top view which illustrates manufacturing processes of thelight emitting apparatus according to the invention.

FIG. 13 is a top view which illustrates manufacturing processes of thelight emitting apparatus according to the invention.

FIG. 14 is a top view which illustrates manufacturing processes of thelight emitting apparatus according to the invention.

FIG. 15 is a top view which illustrates a construction of the pixelsection of the light emitting apparatus according to the invention.

FIG. 16 is a top view which illustrates a construction of the pixelsection of the light emitting apparatus according to the invention.

FIG. 17 is a circuit diagram equivalent to a pixel.

FIG. 18 shows an example of a process to manufacture semiconductorlayers to be adopted in the TFT constituting the light emittingapparatus according to the invention.

FIG. 19 shows an example of a process to manufacture semiconductorlayers to be adopted in the TFT constituting the light emittingapparatus according to the invention.

FIGS. 20A to 20C show an example of a process to manufacturesemiconductor layers to be adopted in the TFT constituting the lightemitting apparatus according to the invention.

FIG. 21 shows an example of a process to manufacture semiconductorlayers to be adopted in the TFT constituting the light emittingapparatus according to the invention.

FIGS. 22A to 22G are views which show applications of the invention.

FIGS. 23A and 23B show one construction of the EL module.

FIG. 24 is a graph which shows SIMS measurement data (secondary ion massspectrometry) of the silicon nitride film.

FIG. 25 is a graph which shows FT-IR measurement data of the siliconnitride film.

FIG. 26 is a graph which shows measurement of the transmittance of thesilicon nitride film.

FIG. 27 is a graph which shows the C-V characteristics before and afterthe BT stress test of the MOS construction.

FIGS. 28A and 28B are graphs which show the C-V characteristics beforeand after the BT stress test of the MOS construction.

FIGS. 29A and 29B are views which illustrate the MOS construction.

FIG. 30 is a view which illustrates a sputtering apparatus.

FIGS. 31A and 31B are cross-sectional views which illustrate theconstruction of the pixel section of the light emitting apparatusaccording to the invention.

FIGS. 32A and 32B are cross-sectional views which illustrate theconstruction of the pixel section of the light emitting apparatusaccording to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of the invention will be described with reference to theaccompanied drawings. Common components among several drawings have samereference numerals.

FIG. 1 shows an exemplary construction of a light emitting apparatus ofthe active matrix driving method according to the invention. TFTs areprovided in a pixel section 302 and a driving circuit section 301 whichis formed in the peripheral region of the pixel section 302. Thesemiconductor layer forming the channel forming region of the TFT maycomprise amorphous silicon or polycrystalline silicon. The apparatusaccording to the invention may use either type of silicon.

The substrate 101 comprises a glass substrate or an organic resinsubstrate. The organic resin has less weight than the glass, which isadvantageous to reduce the weight of the light emitting apparatus as awhole. Organic resin such as polyimide, polyethylene terephthalate(PET), polyethylene naphthalate (PEN), polyether sulfone (PES), andaramid is applicable to manufacture the light emitting apparatus. Bariumborosilicate glass and almino-borosilicate glass, which are known asno-alkali glass, are preferred to be used as a glass substrate. Thethickness of the glass substrate may be 0.5 to 1.1 mm, however, if it isnecessary to reduce the weight of the apparatus, the thickness should bereduced. It is desirable to employ a glass with small specific densitysuch as 2.37 g/cm³ to further more reduce the weight.

As shown in FIG. 1, a n-channel type TFT 303 and p-channel type TFT 304are formed in the driving circuit section 301, and a n-channel typefirst TFT 305, a p-channel type fourth TFT 306 and a capacity section307 are formed in the pixel section 302. The fourth TFT 306 connects toan anode layer 126 of the light emitting element 309.

These TFTs comprise semiconductor layers 103 to 106 on the firstinorganic insulation layer 102 comprising silicon nitride or siliconoxynitride, a gate insulation film 108, and gate electrodes 110 to 113.A second inorganic insulation layer 114 comprising silicon nitride orsilicon oxynitride containing hydrogen is formed on the gate electrode.The second inorganic insulation layer 114 in combination with the firstinorganic insulation layer 102 serves as a protective film whichprevents contamination of the semiconductor layers caused by diffusionof impurities such as moisture or metal into the semiconductor layers.

The first organic insulation layer 115 of 0.5 to 1 μm thicknesscomprising one of polyimid, polyamide, polyimidamide, acrylic, BCB(benzocyclobutene) is formed as a planarizing layer on the secondinorganic insulation layer 114. The first organic insulation layer 115is formed by spin coating one of the above organic compounds, thenapplying calcination. The organic insulation material is hygroscopic andabsorbs and occludes moisture. When the occluded moisture is released,oxygen is supplied to the organic compound contained in the lightemitting element formed over the organic insulation layer, whichdeteriorates the organic light emitting element. To prevent theocclusion and the release of moisture, a third inorganic insulationlayer 116 of 50 to 200 nm thickness is formed on the first organicinsulation layer 115. The third inorganic insulation layer 116 must be afine film in order to adhere to the underlining layer more securely foracting as a barrier. The layer 116 is formed preferably by sputteringwith inorganic insulation material selected from silicon nitride,silicon oxynitride, aluminum oxynitride and aluminum nitride.

The organic light emitting element 309 is formed on the third inorganicinsulation layer 116. In a light emitting apparatus emitting lightthrough the substrate 101, ITO layer (indium oxide, tin) is formed as ananode layer 126 on the third inorganic insulation layer 116. ITO may beadded with zinc oxide or gallium for planarizing, or reducing theresistance. Wirings 117 to 125 are formed prior to the formation of theanode layer 126, overlap with the anode layer 126 over the thirdinorganic insulation layer 116 to form an electric connection.

The second organic insulation layer (barrier layer) 128 which separateseach pixel is formed of material selected from polyimide, polyamide,polyimideamide, acrylic and benzocyclobutene (BCB). Thermosettingmaterial or photo-curing material is applicable. The second organicinsulation layer (barrier layer) 128 is formed by applying the one ofthe above organic insulation material with thickness of 0.5 to 2 μm tocover all surface. Then, an opening fitting to the anode layer 126 isformed. At this time, the opening is formed so as to cover the end ofthe anode layer 126 and the inclination angle on its side is 35 to 45degrees. The second organic insulation layer (barrier layer) 128 extendsnot only over the pixel section 302 but also over the driving circuitsection 301 and covers the wiring 117 to 124, thus, it also serves as aninterlayer insulation film between layers.

The organic insulation material is hygroscopic and absorbs and occludesmoisture. When the occluded moisture is released, the moisture issupplied to the organic compound of the light emitting element 309,which deteriorates the organic light emitting element. To prevent theocclusion and the release of moisture, a fourth inorganic insulationlayer 129 of 10 to 100 nm thickness is formed on the second organicinsulation layer 128. The fourth inorganic insulation layer 129 isformed with an inorganic insulation material comprising nitrides.Particularly, it is formed with an inorganic insulation materialselected from silicon nitride, aluminum nitride and aluminum oxynitride.The fourth inorganic insulation layer 129 is formed so as to cover theupper surface and side surface of the second organic insulation layer128, and its end overlapping with the anode layer 126 is tapered.

The organic light emitting element 309 is formed with an anode layer126, a cathode layer 131 comprising alkali metal or alkali earth metal,and an interposing organic compound layer 130 containing light emittingmaterial. The organic compound layer 130 containing the light emittingmaterial is formed by laminating one or more layers. Each layer is namedaccording to its purpose and function; a positive hole injection layer,a positive hole transferring layer, a light emitting layer, an electronstransferring layer and an electrons injection layer. These layers can beformed with one of low molecular weight organic compounds, middlemolecular weight organic compounds, high molecular weight organiccompounds, or combination of two of the above compounds appropriately.Also, a mixed layer comprising mixture of the electron transferringmaterial and the positive hole transferring material, or a mixedconnection forming mixed region between each interface can be made.

The cathode layer 131 is formed with alkali metal or alkali earth metalhaving smaller work function, such as magnesium (Mg), lithium (Li) orcalcium (Ca). Preferably, an electrode comprising MgAg (a mixture of Mgand Ag with ratio of 10:1) may be used. Other materials suitable to theelectrode include MgAgAl, LiAl and LiFAl. The combination of fluoride ofalkali metal or alkali earth metal, and low resistance metal such asaluminum can be used, as well. The cathode layer 131 as a commonelectrode is formed across a plurality of pixels, and connects to thewiring 120 outside of the pixel section 302 or between the pixel section302 and the driving circuit section 301, then leads to an externalterminal. In FIG. 1, the connection 310 is shown in the region enclosedby the dotted line.

On that layer, a fifth inorganic insulation layer 132 may be formed withone of silicon nitride, diamond-like-carbon (DLC), aluminum oxynitride,aluminum oxide or aluminum nitride. Particularly, the DLC film is knownto have a high gas barrier characteristic against oxygen, CO, CO₂ andH₂O. It is desirable to form the fifth inorganic insulation layer 132 insuccession after the formation of the cathode 131 without exposing thesubstrate to the atmosphere. A buffer layer made of silicon nitride maybe provided under the fifth inorganic insulation layer 132 in order toimprove adhesion.

Although not shown in the figure, a sixth inorganic insulation layer of0.5 to 5 nm thickness which allows flow of a tunnel current may beformed between the anode layer 126 and the organic compound layer 130containing light emitting material. The sixth inorganic insulation layerhas an effect to prevent short circuit caused by any irregularity on thesurface of the anode, and an effect to prevent alkali metal used for thecathode, or the like, from diffusing to the lower layer.

The second organic insulation layer 128 formed over the pixel section302 extends to the driving circuit section 301, and seal patterns 133are formed on the fourth inorganic insulation layer 129 formed on thesecond organic insulation layer 128. Some or all of the seal patterns133 overlap with the driving circuit section 301 and the wiring 117which connects the driving circuit section 301 and the input terminal,which reduces the area of the frame region (peripheral region of thepixel section) of the light emitting apparatus.

A sealing plate 134 is secured via the seal patterns 133. The sealingplate 134 may comprise metal such as stainless steel and aluminum. Also,you may use a glass substrate. Desiccant 135 such as barium oxide may beincluded in the region surrounded by the seal patterns 133 and thesealing plate 134, in order to prevent deterioration caused by moisture.The sealing plate made of an organic resin may be flexible and have 30to 120 μm thickness. The surface of the sealing plate may be coated withan inorganic insulation material such as DLC and silicon nitride, as agas barrier layer. One exemplary material for the seal patterns is epoxyadhesive. The side surface of the seal patterns may be coated with afilm comprising inorganic insulation material, which prevents vapor frompenetrating from the side surface.

In FIG. 1, the first TFT 305 has a multi-gate construction, completedwith a lightly doped drain (LDD) to reduce the off current. Thep-channel type fourth TFT 306 is provided with an impurity regionoverlapping with the gate electrode.

The top view of one pixel in the pixel section provided with the aboveTFT is shown in FIG. 2. In order to illustrate the arrangement of eachTFT clearly, the patterns of the light emitting element 309, the secondorganic insulation layer 128 and the fourth inorganic insulation layer129 are not shown in FIG. 2. One pixel contains a first TFT 305, asecond TFT 311, a third TFT 312, a fourth TFT 306 and a capacity section307.

FIG. 17 schematically shows a circuit equivalent to the constructionshown in FIG. 2. FIG. 1 shows the cross section across the line A-A′ ofFIG. 2. FIG. 3 shows the cross section across the line B-B′, and FIG. 4shows the cross section across the line C-C′, of FIG. 2.

One exemplary construction of the second organic insulation layer 128and the fourth inorganic insulation layer 129 in the pixel section isshown in FIG. 15, in which both of the second organic insulation layer128 and the fourth inorganic insulation layer 129 cover the periphery ofthe anode layer 126. In another exemplary construction shown in FIG. 16,the second organic insulation later 128 may cover only two sides of theanode layer 126, while the fourth inorganic insulation layer 129 maycover all sides of the anode layer 126. Of course, the construction of apixel shown in this figure is only example, and is not a requirement ofthe invention.

Although not shown in FIG. 1, the driving circuit section 301 hasdifferent circuitry for the gate signal driving circuit and the datasignal driving circuit. The wirings 118 and 119 are connected to then-channel type TFT 303 and the p-channel type TFT 304, respectively, andthese TFTs, in turn, can be used to form a shift register, a latchcircuit or a buffer circuit.

An input terminal 308 is formed from a wiring formed from the same layeras the gate electrode, or a wiring formed on the third inorganicinsulation layer 116. FIG. 1 shows an example of an input terminal 308formed from the same layer as the gate electrode, that is, the inputterminal 308 is formed from conducting layers 109 and 127. Theconducting layer 127 is formed of oxide conductive material, at the timewhen the anode layer 126 is formed. In practice, the part exposed to thesurface is covered with the oxide conductive material to prevent theincrease of surface resistance due to oxidation. FIG. 7 is a detailedillustration of the input terminal 308. FIG. 7A shows the top view, andFIGS. 7B and 7C show cross-sectional views across the line D-D′ andE-E′, respectively. The input terminal 308 is formed with the conductivelayers 109 and 127.

As shown in FIG. 1, the first inorganic insulation layer 102 and thesecond inorganic insulation layer 114 are formed so as to sandwich thesemiconductor layers 105 and 106. On the other hand, the organic lightemitting element 309 is surrounded by the third inorganic insulationlayer 116, the fifth inorganic insulation layer 132 and the fourthinorganic insulation layer 129. In other words, the semiconductor layersof the TFT and light emitting elements are coated with the inorganicinsulation layers, respectively. The inorganic insulation layers aremade from films of silicon nitride or silicon oxynitride, which forms abarrier against vapor and ionic impurities.

The possible source of alkali metal such as sodium which contaminatesthe first TFT 305 and the fourth TFT 306 includes the substrate 101 andthe organic light emitting element 309. In order to prevent thecontamination from them, the first TFT 305 and the fourth TFT 306 aresurrounded by the first inorganic insulation layer 102 and the secondinorganic insulation layer 114. As the organic light emitting element309 suffers the severest damage from oxygen and moisture, a thirdinorganic insulation layer 116, a fourth inorganic insulation layer 129,and a fifth inorganic insulation layer 132 are formed with inorganicinsulation material to prevent the contamination by oxygen or moisture.Also, these inorganic insulation layers serve to prevent the alkalimetal element of the organic light emitting element 309 from diffusingto other sections.

FIG. 5 shows an outside view of a substrate comprising components of thelight emitting apparatus illustrated in FIGS. 1 to 4. The substrate 101is provided with a pixel section 302, gate signal driving circuits 301 aand 302 b, a data signal driving circuit 301 c, a connection to thecathode layer 310, an input/output terminal 308 and a wiring or a groupof wirings 117. Seal patterns 133 are provided so that some or all ofthe patterns 133 overlap with the gate signal driving circuits 301 a and301 b, data signal driving circuit 301 c, and the wiring or the group ofwirings 117 which connects these driving circuit sections to the inputterminal, in order to reduce the area of the frame region (peripheral ofthe pixel section) of the light emitting apparatus. Although FIG. 5shows only one cathode layer connection 310, the connection 310 may beprovided on any location around the pixel section 302, as long as itdoes not interfere with the driving circuit sections 301 a to 301 c.

As shown in FIG. 6, a plurality of the substrates 101 (101 a to 101 d)having above construction are provided on a mother glass 201, andseparated along the cutting lines 202 after the formation of one of thefourth inorganic insulation layer, the cathode layer, the fifthinorganic insulation layer or the sealing plate. The substrates areseparated with a diamond cutter or a laser cutter. In order to make theseparating process easier, the third to the fifth inorganic insulationlayers and the first and the second organic insulation layers arepreferably removed along the cutting lines 202.

As described, a TFT and a light emitting element are combined to form apixel section to complete a light emitting apparatus. In the lightemitting apparatus thus manufactured, driving circuits can be formed onthe same substrate by using TFTs as the pixel section. As shown in FIG.1, by surrounding the upper surface and the lower surface of thesemiconductor film, the gate insulation film and the gate electrode,which are major components of a TFT, with blocking layers and theprotective films comprising silicon nitride or silicon oxynitride, thisconstruction prevents these components from being contaminated by alkalimetal and organic material. The organic light emitting element, in turn,contains the alkali metal in part, and is surrounded by a protectivefilm comprising one of silicon nitride, silicon oxynitride or DLC, and agas barrier layer comprising an insulation film mainly consisting ofsilicon nitride or carbon, so that this construction prevents thepenetration of oxygen or moisture from the outside.

The film comprising silicon nitride used for the inorganic insulationlayers in this embodiment (silicon nitride film) is a highly fine filmformed by the RF sputtering, according to the conditions shown in thetable 1 (A typical example is illustrated). “RFSP-SiN” in the tableindicates a silicon nitride film formed by the RF sputtering. “T/S” isthe distance between the target and the substrate.

TABLE 1 RFSP-SiN processing condition representative processingcondition example comments gas N₂ or (noble gas)/N₂ Ar/N₂ each purity is4N or more gas flow ratio N₂: 30~100%, Ar:N₂ = noble gas may be noblegas: 0~70% 20:20(sccm) introduced as gas for heating form the backsideof a substrate pressure (Pa) 0.1~1.5 0.8 flequency (MHz) 13~40 13.56power (W/cm²)  5~20 16.5 substrate RT (Room 200 temperature (° C.)Temperature) ~350 target material material carved out of Si(1~10 Ωcm)single crystalline Si ingot T/S (mm)  40~200 60 back-pressure (Pa) 1 ×10⁻³ or less (preferably 3 × 10⁻⁵ using turbo-molecular 3 × 10⁻⁵ orless) pump or cryopump

Ar, as sputtering gas, is introduced to be sprayed on the back surfaceof the substrate to heat the same. The sprayed Ar is ultimately mixedwith N₂ for sputtering. The values shown in the table 1 for forming afilm are only representative values and not limited to those indicatedhere. As long as the physical parameters of the resulting SiN film fallin the range of the physical parameters shown in the table 4 (shownlater), these conditions can be modified appropriately by the operator.

Next, a schematic view of a sputtering apparatus used to form a siliconnitrogen film by the above RF sputtering is shown in FIG. 30. In FIG.30, 30 is a chamber wall, 31 is a movable magnet for forming magneticfield, 32 is a single crystal silicon target, 33 is a protectiveshutter, 34 is a substrate to be processed, 36 a and 36 b are heaters,37 is a substrate chuck device, 38 is an antitack plate and 39 is avalve (conductance valve or main valve). The chamber wall 30 is providedwith gas intake tubes 40 and 41 which introduce N₂ (or mix gas of N₂ andnoble gas), and noble gas, respectively.

Table 2 shows conditions to form a silicon nitride film formed by theconventional plasma CVD method, for reference. “PCVD-SiN” in the tablerefers to a silicon nitride film formed by the plasma CVD method.

TABLE 2 plasma CVD condition PCVD-SiN gas SiH₄/NH₃/N₂/H₂ gas flow ratio(sccm) SiH4:NH3:N2:H2 = 30:240:300:60 pressure (Pa) 159 frequency (MHz)13.56 power (W/cm²) 0.35 substrate temperature (° C.) 325

Table 3 shows the representative values of physical characteristics(physical parameters) of the silicon nitride film formed under theconditions in the table 1, and that formed under the conditions in thetable 2. The differences between “RFSP-SiN (No. 1)” and “RFSP-SiN (No.2)” are attributable to the difference between the film formingapparatuses, and do not impair the function of a silicon nitride filmused as a barrier film according to the invention. The internal stressmay be compressive or tensile, and the sign of the numerical valuechanges accordingly, but the table shows only the absolute value.

TABLE 3 comparison between representative SiN physical parameters SiNprepared by the condition SiN prepared by the condition referring to thepreparing referring to the preparing condition in Table. 1 condition inTable. 2 parameter RFSP-SiN (No. 1) RFSP-SiN (No. 2) PCVD-SiN filmcomments specific inductive 7.02~9.30 ← ~7 capacity refractive index1.91~2.13 ← 2.0~2.1 Wavelength of irradiated light is 632.8 nm internalstress 4.17 × 10⁸  ← 9.11 × 10⁸ (dyn/cm²) etching rate 0.77~1.31 1~8.6~30 LAL500, 20° C. (nm/min) Si concentration 37.3 51.5 35.0 RBS (atomic%) N concentration 55.9 48.5 45.0 RBS (atomic %) H concentration 4 ×10²⁰ — 1 × 10²² SIMS (atoms/cm³) O concentration 8 × 10²⁰ — 3 × 10¹⁸SIMS (stoms/cm³) C concentration 1 × 10¹⁹ — 4 × 10¹⁷ SIMS (atoms/cm³)

As shown in the table 3, the common characteristics in the RFSP-SiN(No. 1) and the RFSP-SiN (No. 2) are lower etching rate (the etchingrate of the etching with LAL 500 at 20° C., ditto) and lower hydrogenconcentration compared to those of the PCVD-SiN film. “LAL500” is the“LAL500 SA buffered hydrofluoric acid” which is solution of NH₄HF₂(7.13%) and NH₄F (15.4%), manufactured by Hashimoto Kasei Co., Ltd. Theabsolute value of the internal stress is less than that of the siliconnitride film formed by the plasma CVD method.

Next, various physical parameters of the silicon nitride film formed bythe inventors under the conditions in table 1 are summarized in thetable 4.

TABLE 4 SiN physical parameters used in the present invention parameterSiN film used in the present invention comments specific inductivecapacity 7.0~9.5 (preferably 7.3~7.7) refractive index 1.85~2.20(preferably 1.90~2.15) Wavelength of irradiated light is 632.8 nminternal stress (dyn/cm²) 2 × 10¹⁰ or less (preferably 5 × 10⁸ or less)etching rate (nm/min) 9 or less (preferably 0.5~3.5) LAL500, 20° C. Siconcentration 35~55 (preferably 37~52) RBS (atomic %) N concentration45~60 (preferably 48~56) RBS (atomic %) H concentration 1 × 10²¹ or less(preferably 5 × 10²⁰ or less) SIMS (atoms/cm³) O concentration 5 ×10¹⁸~5 × 10²¹ (preferably 1 × 10¹⁹~1 × 10²¹) SIMS (atoms/cm³) Cconcentration 1 × 10¹⁸~5 × 10¹⁹ (preferably 1 × 10¹⁸~2 × 10¹⁹) SIMS(atoms/cm³)

The results of the SIMS (secondary ion mass spectrometry) and FT-IR, andthe transmittance, of the above silicon nitride film, are shown in FIGS.24, 25 and 26, respectively. FIG. 26 also shows the silicon nitride filmformed under the conditions of the table 2. The transmission factor isalmost comparable to that of the conventional PCVD-SiN film.

The silicon nitride film used as an inorganic insulation layer accordingto the invention preferably satisfies the parameters shown in the table4. That is, the inorganic insulation layer preferably satisfies one ofthe following conditions; (1) a silicon nitride film with etching rateof 9 nm/min or less (preferably, 0.5 to 3.5 nm/min or less), (2)hydrogen concentration of 1×10²¹ atoms/cm³ or less (preferably 5×10²⁰atoms/cm³ or less), (3) hydrogen concentration of 1×10²¹ atoms/cm³ orless (preferably 5×10²⁰ atoms/cm³ or less), and oxygen concentrationfrom 5×10¹⁸ to 5×10²¹ atoms/cm³ (preferably 1×10¹⁹ to 1×10²¹ atoms/cm³),(4) etching rate of 9 nm/min or less (preferably, 0.5 to 3.5 nm/min orless), and hydrogen concentration of 1×10²¹ atoms/cm³ or less(preferably 5×10²⁰ atoms/cm³ or less), and (5) etching rate of 9 nm/minor less (preferably, 0.5 to 3.5 nm/min or less), hydrogen concentrationof 1×10²¹ atoms/cm³ or less (preferably 5×10²⁰ atoms/cm³ or less), andoxygen concentration from 5×10¹⁸ to 5×10²¹ atoms/cm³ (preferably 1×10¹⁹to 1×10²¹ atoms/cm³).

The absolute value of the internal stress may be 2×10¹⁰ dyn/cm² or less,preferably 5×10⁹ dyn/cm² or less, and more preferably 5×10⁸ dyn/cm² orless. The smaller internal stress can reduce the difference in theenergy level between the films, and further prevent the film frompeeling by the internal stress.

The silicon nitride film formed under condition shown in the Table 1according to this embodiment has a distinct blocking effect against theelements belonging to Group 1 and Group 2 in the periodic table such asNa and Li, and can effectively suppress the diffusion of these mobileions. For example, a metal film made of aluminum with 0.2 to 1.5 wt %(preferably, 0.5 to 1.0 wt %) lithium added is preferred for a cathodelayer of this embodiment in terms of various physical characteristicsincluding charge injection characteristic, or the like. However, whenusing this type of metal film, the lithium may diffuse and damage theperformance of the transistor. To avoid this damage, the presentembodiment completely protects the transistor with inorganic insulationlayers, so that the lithium would not diffuse to the transistor.

This is shown in the data in FIGS. 27 to 29. FIG. 27 is a diagram thatshows the change in the C-V characteristic before and after the BTstress test of the MOS structure which has a silicon nitride film(PCVD-SiN film) as a dielectric formed under conditions of the table 2.The construction of the sample is shown in FIG. 29A, and the effect ofthe diffusion of the lithium an be determined by using Al—Li (lithiumadded aluminum) electrode as the surface electrode. As shown in FIG. 27,the B-T stress test reveals that the C-V characteristic is significantlyshifted, which indicates that the lithium diffused from the surfaceelectrode has a substantial effect.

FIGS. 28A and 28B show the C-V characteristic before and after the BTstress test of the MOS structure which has a silicon nitride film(PCVD-SiN film) formed under conditions of the table 1 as a dielectric.The difference in the tests of FIG. 28A and FIG. 28B is that, an Al—Si(silicon added aluminum film) electrode is used as a surface electrodein the test of FIG. 28A, while an Al—Li (lithium added aluminum film)electrode is used as a surface electrode in the test of FIG. 28B. Theresult shown in FIG. 28B is the result of the measurement of the MOSconstruction shown in FIG. 29B. In FIG. 29B, the films are laminatedwith thermally-oxidized film in order to reduce the effect of differencein energy levels at the interface between the silicon nitride film andthe silicon substrate.

As can be seen from the graphs in FIGS. 28A and 28B, the C-Vcharacteristics before and after the BT stress test have similar shiftpattern, which indicates that there is no effect of lithium diffusion,that is, the silicon nitride film formed under the conditions of thetable 1 effectively serves as a blocking film.

As described, since the inorganic insulation layer used in thisinvention is extremely fine and has such high blocking effect againstmobile elements including Na and Li, it can suppress diffusion ofdegassed components from the planarizing film as well as suppress thediffusion of Li from the Al—Li electrode. Taking advantage of theseeffects, a highly reliable display apparatus can be realized. Theinventors suppose that the inorganic insulation layer can be made finesince silicon clusters cannot easily contaminate the film, as a thinsilicon nitride film is formed on the surface of the single crystalsilicon target, then the silicon nitride film thus manufactured islaminated on the substrate.

Also, as the silicon nitride film is formed by the sputtering method atrelatively low temperature i.e., from the ambient temperature to about200° C., the silicon nitride film which is used as a barrier filmaccording to the invention can be formed on the resin films, which isanother advantage over the plasma CVD method. The above silicon nitridefilm can be used as a part of a gate insulation film when forming it bylaminating.

EMBODIMENTS Embodiment 1

Next, the process of manufacturing the light emitting apparatus shown inFIG. 1 is described with reference to the figures.

In FIG. 8A, the substrate 101 may be one of a glass substrate, a quartzsubstrate or a ceramic substrate. The substrate 101 may comprise asilicon substrate, a metal substrate or a stainless substrate with aninsulation layer formed thereon. A plastic substrate having heatresistance bearable to the processing temperature of the embodiment isacceptable.

A first inorganic insulation layer 102 consisting of an insulation filmsuch as a silicon oxide film, a silicon nitride film or a siliconoxynitride film (SiO_(x)N_(y)) is formed on the substrate 101. A typicalexample has a two-layer construction, in which the first siliconoxynitride film of 50 nm thickness is formed using SiH₄, NH₃ and N₂O asreaction gases, and the second silicon oxynitride film of 100 nmthickness is formed on the first film, using SiH₄ and N₂O as reactiongases.

The semiconductor layer as an activation layer can be obtained bycrystallizing the amorphous semiconductor film formed on the firstinorganic insulation layer 102. The amorphous semiconductor film isformed with thickness of 30 to 60 nm, and crystallized by heating, orirradiating laser beams. There is no restriction on the material of theamorphous semiconductor film, however, silicon or silicon germanium(Si_(1-x)Ge_(x); 0<x<1. Representative value for x is 0.001 to 0.05)alloy may be preferably used.

In a representative example, the amorphous silicon film of 54 nmthickness is formed by the plasma CVD method using SiH₄ gas. Forcrystallization, a pulse oscillating or a continuous oscillating excimerlaser, or a YAG laser, a YVO₄ laser or a YLF laser which are doped withone of Cr, Nd, Er, Ho, Ce, Co, Ti or Tm can be used. When using one of aYAG laser, a YVO₄ laser or a YLF laser, the second harmonic to thefourth harmonic can be used. When using one of these lasers, the laserbeam irradiated from the laser oscillator can be linearly collected byan optical system to irradiate on the semiconductor film. The conditionof the crystallization can be selected by the operator appropriately.

In crystallization, certain metal element such as nickel which can serveas a catalyst for the crystallization of the semiconductor can be added.An exemplary process of crystallization is; holding a solutioncontaining nickel on the amorphous silicon film, dehydrogenating (500°C. for one hour), heat-crystallizing (550° C. for four hours), thenirradiating the second harmonic of a continuous oscillating laserselected from a YAG laser, a YVO₄ laser, or a YLF laser, in order toimprove the crystallization.

The resulting crystalline semiconductor film is etched in a desired formby photolithography using a photo mask (1) to form semiconductor layers103 to 107 separated like islands. FIG. 12 shows a top view of the pixelat this point.

Also, after crystallization of the amorphous semiconductor film, thefilm can be doped with p-type impurity element in order to controlthreshold of the TFT. P-type impurity elements include the elementsbelonging to Group 13 in the periodic table, such as boron (B), aluminum(Al) and garium (Ga).

Next, as shown in FIG. 8B, a gate insulation film 108 covering thesemiconductor layers 103 to 107 separated like islands is formed. Thegate insulation film 108 of 40 to 150 nm thickness is formed by theplasma CVD method or the sputtering using inorganic insulation materialsuch as silicon oxide or silicon oxynitride. This gate insulation layercan use insulation film containing silicon as a single layerconstruction or a laminated construction.

A first conductive film 10 of 10 to 50 nm thickness comprising tantalumnitride (TaN), and a second conductive film 11 of 100 to 400 nmthickness comprising tungsten (W) are laminated on the gate insulationfilm 108 in order to form a gate electrode. Other conductive materialfor gate electrode may be selected from Ta, W, Ti, Mo, Al, Cu, or analloy or a chemical compound having one of above elements as a maincomponent. Also, a semiconductor film including a poly-crystallinesilicon film doped with an impurity element such as phosphorous may beused. Furthermore, a combination of the first conductive film of atantalum film (Ta) and the second conductive film of a W film, acombination of the first conductive film of a tantalum nitride (TaN)film and the second conductive film of a Al film, or a combination ofthe first conductive film of a tantalum nitride (TaN) film, and thesecond conductive film of Cu film may be also applied.

Next, as shown in FIG. 8C, a mask 12 by which gate electrode patternsare formed is formed by photolighography using a photo mask (2). Afterthat, the first etching is performed with dry-etching, for example, ICP(Inductively Coupled Plasma) etching. There is no restriction on theetching gas, however, CF₄, Cl₂ and O₂ may be used for etching of W andTaN. In the first etching, predetermined biasing voltage is applied tothe substrate to make inclination angle of 15 to 50 degrees on the sidesurface of the formed electrode patterns 13 to 17. The first etchingfacilitates simultaneous etching of the exposed region on thisinsulation film, and a region thinner than the other region by 10 to 30nm is formed.

Next, the condition is changed to the second etching condition, andanisotropic etching is performed on the W film using SF₆, Cl₂ and O₂ asetching gases, and applying predetermined biasing voltage to thesubstrate. Gate electrodes 110 to 113 and a wiring 109 of an inputterminal are thus formed. After that, the mask 12 is removed. The secondetching facilitates simultaneous etching of the exposed region on thisinsulation film, and a region thinner than the other region by 10 to 30nm is formed. FIG. 13 shows a top view of the pixel section at thispoint.

After formation of the gate electrodes, a first doping is performed asshown in FIG. 9A to form first n-type impurity regions 18 to 22 in thesemiconductor layer. These first n-type impurity regions are formed in aself-aligned manner using the gate electrode as a mask. The dopingcondition can be set appropriately, using 5% PH₃ diluted with hydrogen,and injecting 6×10¹³/cm² dose at 50 kV.

Next, as shown in FIG. 9B, a mask 23 is formed by photolithography usinga photo-mask (3) and a second doping is performed. The second dopinguses 5% PH₃ diluted with hydrogen, and injects 3×10¹⁵ atoms/cm² dose at65 kV to form second n-type impurity regions 24, 25 and a third n-typeimpurity region 26. In the semiconductor layer 103, a second n-typeimpurity region 24 is formed outside of the gate electrode, and a thirdn-type impurity region 26 is formed in the position overlapping with thegate electrode, in a self-aligned manner using the gate electrode as amask. The second n-type impurity region 25 is formed in thesemiconductor layer 105 by the mask 23.

Next, as shown in FIG. 9C, a mask 27 is formed by photolithography usinga photo-mask (4), and a third doping is performed. The third doping uses5% PH₃ diluted with hydrogen, and injecting 2×10¹⁶ atoms/cm² dose at 80kV to form p-type impurity regions 28 to 30 in the semiconductor layers104, 106 and 107.

As the result of the above processes, the impurity regions having eithern-type conductivity or p-type conductivity are formed in eachsemiconductor layer, respectively. As shown in FIG. 10A, in thesemiconductor layer 103, the second n-type impurity region 24 acts as asource or drain region, and the third n-type impurity region 26 acts asa LDD region. In the semiconductor layer 104, the p-type impurity region28 acts as a source or drain region. In the semiconductor layer 105, thesecond n-type impurity region 25 acts as a source or drain region, andthe first n-type impurity region 20 acts as a LDD region. In thesemiconductor layer 106, the p-type impurity region 29 acts as a sourceor drain region.

Next, a second inorganic insulation layer 114 covering almost all thesurface is formed. The second inorganic insulation layer 114 of 100 to200 nm thickness is formed using the plasma CVD or the sputtering, withan inorganic insulation material containing silicon and hydrogen. Thepreferred example is an silicon oxynitride film of 100 nm thicknessformed by the plasma CVD using SiH₄, N₂O, NH₃, and H₂. After that,heating at 410° C. for one hour is performed in nitrogen atmosphere. Thepurpose of this heating process is to hydrogenate the silicon oxynitridefilm in order to make it a source of the hydrogen.

Next, as shown in FIG. 10B, a first organic insulation layer 115 of 0.5to 1 μm is formed on the second inorganic insulation layer 114.Thermosetting acrylic material can be used as the organic insulationmaterial, which is spin-coated, then calcined at 250° C. to formplanarized film. On this film, a third inorganic insulation layer 116 of50 to 100 nm thickness is formed.

When forming the third inorganic insulation layer 116, the substratehaving the second organic insulation layer 114 formed thereon is heatedat 80 to 200° C. for dehydration. An exemplary material suitable for thethird inorganic insulation layer 116 is silicon nitride film formed bysputtering using silicon as a target. Conditions for forming a film canbe selected appropriately. Preferably, nitrogen (N₂) or mix of nitrogenand argon is applied by RF power for sputtering. The substrate may beprocessed in the temperature from room temperature to 200° C.

Next, as shown in FIG. 10C, mask patterns are formed by photolithographyusing photo-mask (5), and a contact hole 30 and an opening 31 of theinput terminal are formed by dry-etching. The conditions of thedry-etching are as follows; etching the third inorganic insulation layer116 and the first organic insulation layer 115 using CF₄, O₂ and He,then, etching the second inorganic insulation layer and the gateinsulation layer using CHF₃.

After that, as shown in FIG. 11A, wirings and pixel electrodes areformed using Al, Ti, Mo or W. A photo-mask (6) is used to form wirings.For example, a laminated film of a Ti film of 50 to 250 nm thickness andan alloy film comprising Al and Ti of 300 to 500 nm thickness may beused. The wirings 117 to 125 are thus formed. Then ITO of 30 to 120 nmthickness is formed by the sputtering, and then predetermined patternsare formed on it by photolithography using the photo mask (7). An anodelayer 126 of the light emitting element is thus formed, and ITO film 127is formed on the wiring at the input terminal. FIG. 14 shows the topview of the pixel at this stage.

Next, as shown in FIG. 11B, a second organic insulation layer 128 isformed. This layer is formed with acrylic material similar to the firstorganic insulation layer 115. Then, openings are formed using aphoto-mask (8) over the anode layer 126, a connection of the cathodelayer 310, and the input terminal. The second organic insulation layer128 is formed so as to cover the end of the anode 126, and its sidesurface has an inclination angle of 40 degree.

The organic insulation material is hygroscopic and occludes moisture. Inorder to prevent the occlusion and release of moisture, a fourthinorganic insulation layer 129 of 10 to 100 nm thickness is formed onthe second organic insulation layer 128. The fourth inorganic insulationlayer 129 is formed with inorganic insulation material comprisingnitride. The fourth inorganic insulation layer 129 is formed from asilicon nitride film manufactured by the sputtering. The applicable filmis similar to that for the third inorganic insulation layer 116. Thefourth inorganic insulation layer 129 covers the upper surface and theside surface of the second organic insulation layer 128, with a taperedend overlapping with the anode layer 126. Thus, the fourth inorganicinsulation layer 129 is formed at the input terminal so as to cover theside surface of the opening formed over the second organic insulationlayer 128, so that it prevents penetration of moisture from this region.

Then, an organic compound layer 130 containing light emitting materialis formed. An cathode layer 131 is formed on the organic compound layercontaining light emitting material, by the sputtering or resistanceheating deposition. The cathode layer 131 is formed by using calciumfluoride or cesium fluoride as a cathode material and depositing it byvacuum deposition.

The cathode 131 is formed from laminated structure of lithium fluorideand aluminum. Noble gas (typically argon) is used for sputtering gas.Ions of sputtering gas are not only accelerated by sheath electric fieldand clash with a target, but also are accelerated by weak sheathelectric field and implanted into the organic compound layer 130containing a light emitting material under the anode. The noble gasprevents molecules or atoms from displacing by positioning betweenlattices of the organic compound layers and improves stability of theorganic compounds. Further, the fifth inorganic insulation layer 132formed on the anode 131 is formed of silicon nitride or DLC film. Theions of noble gas (typically argon) are accelerated by weak sheathelectric field on the side of substrate and implanted into the organiccompound layer 131 under the anode 131 passing through the anode. Then,an effect of improving stability of the organic compound can beobtained.

Finally, seal patterns are formed and a sealing plate is adhered tomanufacture a light emitting apparatus as shown in FIG. 1.

Embodiment 2

This embodiment has a different construction than that of the embodiment1 for the pixel section, as illustrated in FIGS. 31 and 32. In thisembodiment, the processes from the beginning to the formation of thethird inorganic insulation layer 116 wiring 123, and anode 126 are sameas FIG. 1.

As shown in FIG. 31A, a second organic insulation layer 180 covering theend of the anode 126 is formed of a photosensitive, negative-typeacrylic resin. Thus, the end where the second organic insulation layer180 contacts with the anode 126 has a inclined surface having acurvature as shown in Figure, the shape of which can be expressed by atleast two curvatures R1 and R2. The center of the R1 is located abovethe wiring, while that of the R2 is located below the wiring. This shapemay vary slightly depending on the exposure, but the thickness of thefilm is 1.5 μm and the value for R1 and R2 is 0.2 to 2 μm. The inclinedsurface has continuously varying curvatures.

Then, along the inclined surface having these smooth curvatures, afourth inorganic insulation layer 129, an organic compound layer 130, acathode layer 131 and a fifth inorganic insulation layer 132 are formedas shown in FIG. 31B. The shape of the section of this second organicinsulation layer 180 has an effect of mitigating stress (especially, aregion where the anode 126, the fourth inorganic insulation layer 129and the organic compound layer 130 overlap), which makes it possible toprevent the light emitting element from deteriorating from this endsection. That is, this construction can prevent the progressivedeterioration which begins from the peripheral of the pixel then expandsto other region. In other words, a region not emitting light cannotexpand.

FIG. 32A shows an example wherein the second organic insulation layer181 is formed with a photosensitive positive-type acrylic resin insteadof the photosensitive negative-type acrylic resin. In this case, theshape of the section at the end is different. The curvature radius R3 is0.2 to 2, with its center located below the anode layer 126. Afterformation of the second organic insulation layer 181, a fourth inorganicinsulation layer 129, an organic compound layer 130, an cathode layer131 and a fifth inorganic insulation layer 132 are formed along theinclined surface having curvatures as shown in FIG. 32B. The similareffect can be obtained by this construction.

This embodiment can be implemented in combination with the embodiments 1and 2.

Embodiment 3

For the embodiments 1 to 2, there is no restriction on the constructionof the organic compound layer in the light emitting element 309, sothat, any known construction is applicable. The organic compound layer130 has a light emitting layer, a positive holes injecting layer, anelectrons injecting layer, a positive holes transferring layer and anelectrons transferring layer, and may have a construction wherein theselayers are laminated, or a construction wherein a part or all of thematerials forming these layers are mixed. Particularly, the lightemitting layer, the positive holes injecting layer, the electronsinjecting layer, the positive holes transferring layer and the electronstransferring layer are included. A basic EL element has a constructionwherein an anode, a light emitting layer, a cathode are laminated inthis order. Other possible construction includes a construction whereinthe layers are laminated in an order of an anode, a positive holesinjection layer, a light emitting layer and a cathode, or an order of ananode, a positive holes injecting layer, a light emitting layer, anelectrons transferring layer and a cathode.

Typically, the light emitting layer is formed using organic compound.However, it may be formed with charge injection transferring materialincluding organic compound or inorganic compound and a light emittingmaterial, it may contain one or more layers made of organic compoundselected from low molecular organic compounds, middle molecular organiccompounds, and polymer organic compounds, and the light emitting layermay be combined with inorganic compound of an electrons injectiontransferring type or a positive holes injection transferring type. Themiddle molecular organic compounds refer to organic compounds which arenot sublimatic and have molecular numbers of 20 or less, or length ofcatenated molecules does not exceed 10 μm.

The applicable light emitting materials include metal complex such astris-8-quinolinolatoaluminum complex or bis (benzoquinolinolato)beryllium complex as low molecular organic compounds, phenylanthracenederivative, tetraaryldiamine derivative and distyrylbenzen derivative.Using one of the above materials as a host substance, coumarinderivative, DCM, quinacridone and rubrene may be applied. Other knownmaterials may be applicable as well. Polymer organic compounds includepolyparaphenylenevinylenes, polyparaphenylens, polythiophenes andpolyfluorenes, including, poly (p-phenylene vinylene): (PPV), poly(2,5-dialkoxy-1,4-phenylene vinylene):(RO-PPV), poly[2-(2′-ethylhexoxy)-5-methoxy-1,4-phenylene vinylene]:(MEH-PPV), poly[2-(dialkoxyphenyl)-1,4,-phenylene vinylene]:(ROPh-PPV), poly(p-phenylene):(PPP), poly (2,5-dialkoxy-1,4-phenylene): (RO-PPP), poly(2,5-dihexoxy-1,4-phenylene), polythiophene:(PT), poly(3-alkylthiophene): (PAT), poly (3-hexylthiophene):(PHT), poly(3-cyclohexylthiophene):(PCHT), poly(3-cyclohexyl-4-methylthiophene):(PCHMT), poly(3,4-dicyclohexylthiophene):(PDCHT), poly[3-(4-octylphenyl)-thiophene]:(POPT), poly[3-(4-octylphenyl)-2,2-bithiophene]):(PTOPT), polyfluorene:(PF), poly(9,9-dialkylfluorene):(PDAF.), poly (9,9-dioctylfluorene):(PDOF).

Inorganic compounds, such as diamond-like carbon (DLC), Si, Ge andoxides and nitrides thereof, may be used for the charge injectiontransferring layer. The above materials may furthermore be added with P,B or N appropriately. Also, the charge injection transferring layer maybe oxides, nitrides or fluorides of alkali metals or alkali earthmetals, or compounds or alloys of the alkali metals or alkali earthmetals with at least Zn, Sn, V, Ru, Sm and In.

The listed materials are only examples. By using these materials,functional layers such as a positive holes injection transferring layer,a positive holes transferring layer, an electrons injection transferringlayer, an electrons transferring layer, a light emitting layer, anelectron block layer and a positive holes block layer can bemanufactured and laminated appropriately to form a light emittingelement. Also, a mixed layer or a mixed connection which combines theselayers may be formed, as well. The electroluminescence has two types oflight, i.e. a light which is emitted when the state moves back fromsinglet excited state to the ground state (fluorescence), and a lightwhich is emitted when the state moves back from triplet excited state tothe ground state (phosphorescence). The electroluminescence elementaccording to the invention can use either or both of these lights.

This embodiment can be implemented in combination with embodiments 1 to3.

Embodiment 4

The anode layer 126 and the cathode layer 131 of the light emittingelement 309 in the embodiment 1 can be reversed. In this case, thelayers are laminated in the order of the cathode layer 126, the organiccompound layer 130 and the anode layer 131. In place of ITO, Metalnitride (titanium nitride, for example) with a work function of 4 eV ormore formed with a thickness of 10 to 30 nm to have translucency alsocan be used for the cathode layer 126. Further, the cathode layer 131can be formed from the lithium fluoride layer of 0.5 to 5 nm thicknesson an aluminum layer of 10 to 30 nm thickness.

This embodiment can be implemented in combination with the embodiments 1to 4.

Embodiment 5

An embodiment of manufacturing process of the semiconductor layer to beapplied to the TFT in the embodiment 1 will be described with referenceto FIG. 18. In this embodiment, continuous oscillating laser beams scanthe amorphous silicon film formed on the insulation surface tocrystallize the same.

A barrier layer 402 comprising a silicon oxynitride film of 100 nmthickness is formed on a glass substrate 401, as shown in FIG. 18A. Onthe barrier layer 402, an amorphous silicon film 403 of 54 nm thicknessis formed by the plasma CVD method.

The laser beams are continuous beams irradiated with continuousoscillation from an Nd:YVO₄ laser oscillator, and the second harmonic(532 nm) obtained by a wavelength conversion element is irradiated. Thecontinuous oscillating laser beams are collected in an oblong shape byan optical system, and by moving relative positions of the substrate 401to the point from which the laser irradiate the beam 405, the amorphoussilicon film 403 is crystallized to form a crystalline silicon film 404.F20 cylindrical lens can be adopted as the optical system, whichtransforms the laser beam with a diameter of 2.5 mm into an oblong shapewith long axis of 2.5 mm and short axis of 20 μm on the irradiatedsurface.

Of course, other laser oscillator may equally be applicable. As acontinuous solid-state laser oscillator, a laser oscillator using acrystal such as YAG, YVO₄, YLF or YAlO₃, doped with Cr, Nd, Er, Ho, Ce,Co, Ti or Tm may be applicable.

When using the second harmonic (532 nm) of the Nd:YVO₄ laser oscillator,the laser beam of the wavelength is transmitted through the glasssubstrate 401 and the barrier layer 402. Therefore, the laser beam 406may be irradiated from the glass substrate 401 side, as shown in FIG.18B.

Crystallization proceeds from the area to which the laser beam 405 isirradiated, to form a crystalline silicon film 404. The laser beam maybe scanned in either one direction or backwards and forwards. Whenscanning backwards and forwards, the laser energy density may be changedfor each scanning to make gradual crystallization. The scanning may havedehydrogenation effect as well, which is often necessary when anamorphous silicon film is to be crystallized. In that case, the firstscanning may be performed at lower energy density, then, afterdehydrogenation, the second scanning may be performed at higher energydensity to complete the crystallization. Such process can also provide acrystalline semiconductor film in which crystal grains extend in thedirection of laser beam scanning. After these processes, semiconductorlayers are separated like islands, which can be applied to theembodiment 1.

The construction shown in this embodiment is only exemplary. Other laseroscillator, other optical system and combination thereof may beapplicable as long as similar effect can be obtained.

Embodiment 6

An embodiment of manufacturing process of the semiconductor layer to beapplied to the TFT in the embodiment 1 will be described with referenceto FIG. 19. In this embodiment, an amorphous silicon film formed on theinsulation surface is crystallized in advance, then, expanding the sizeof the crystal grains by continuous oscillating laser beams.

As shown in FIG. 19A, a blocking layer 502 and an amorphous silicon film503 are formed on a glass substrate 501 as is in the embodiment 1.Nickel acetate 5 ppm solution is spin-coated to form a catalyst elementcontaining layer 504 in order to add Ni as a metal element to lower thecrystallization temperature and promote the crystallization.

The amorphous silicon film is crystallized by heating at 580° C. forfour hours, as shown in FIG. 19B. Silicide is formed and diffused in theamorphous silicon film by the action of R1, and the crystal growssimultaneously. The resultant crystalline silicon film 506 consists ofbar-shaped or needle-shaped crystals, each of which grows in specificdirection when seen from a macroscopic viewpoint, thus the crystallinedirections are uniform. And, it is characterized by that a plane (110)has a high orientation rate.

As shown in FIG. 19C, scanning by continuous oscillating laser beam 508is performed to improve the quality of the crystallization of thecrystalline silicon film 506. By irradiating the laser beam, thecrystalline silicon film melts and re-crystallize. In thisre-crystallization, the crystal grains extend in the scanning directionof the laser beam. As the surface of the crystalline silicon film isuniform, it is possible to suppress deposition of crystalline grainswith different crystalline plains and formation of dislocations. Afterthese processes, semiconductor layers are separated like islands, whichcan be applied to the embodiment 1.

Embodiment 7

An embodiment of manufacturing process of the semiconductor layer whichcan be applied to the TFT in the embodiment 1 will be described withreference to FIG. 20.

As shown in FIG. 20A, a blocking layer 512 and an amorphous silicon film513 are formed on a glass substrate 511 as is in the embodiment 1. Onthis film, a silicon oxide film of 100 nm thickness is formed as a maskinsulation film 514 by plasma CVD, and an opening 515 is provided. Thenickel acetate 5 ppm solution is spin-coated in order to add Ni as acatalyst element. Ni solution contacts with the amorphous silicon filmat the opening 515.

Next, as shown in FIG. 20B, the amorphous silicon film is crystallizedby heating at 580° C. for four hours. By the action of the catalystelement, the crystal grows from the opening 515 in a direction parallelto the surface of the substrate. The resultant crystalline silicon film517 consists of bar-shaped or needle-shaped crystals, each of whichgrows in specific direction when seen from a macroscopic viewpoint, thusthe crystalline directions are uniform. Also, it is oriented in aspecific direction.

After heating, the mask insulation film 514 is removed by etching toobtain a crystalline silicon film 517 as shown in FIG. 20C. After theseprocesses, semiconductor layers are separated like islands, which can beapplied to the embodiment 1.

Embodiment 8

In the embodiment 6 or 7, after the formation of the crystalline siliconfilm 507 or 517, a process can be added to remove the catalyst elementremaining in the film with concentration of 10¹⁹ atoms/cm³ or more, bygettering.

As shown in FIG. 21, a barrier layer 509 comprising thin silicon oxidefilm is formed on the crystalline silicon film 507, then an amorphoussilicon film added with argon or phosphorous of 1×10²⁰ atoms/cm³ to1×10²¹ atoms/cm³ is formed by the sputtering, as a gettering site 510.

The Ni which is added as a catalyst element can be segregated to thegettering site 510, by heating at 600° C. for 12 hours in a furnaceanneal, or by heating at 650 to 800° C. for 30 to 60 minutes with RTAusing lamp light or heated gas. This process reduces the concentrationof the catalyst element in the crystalline silicon film 507 to 10¹⁷atoms/cm³ or less.

The gettering under similar condition is effective for the crystallinesilicon film formed in the embodiment 5. The minute amount of the metalelement contained in the crystalline silicon film formed by irradiatinglaser beams to the amorphous silicon film can be removed by thisgettering.

Embodiment 9

FIG. 23 shows an embodiment to make a module from an EL panel in whichthe pixel section and the driving circuit section are integrally formedon the glass substrate, as shown in the embodiment 1. FIG. 23Aillustrates an EL module on which an IC containing a power supplycircuit for example is mounted on the EL panel.

In FIG. 23A, the EL panel 800 is provided with a pixel section 803having a light emitting element for each pixel, a scanning line drivingcircuit 804 for selecting a pixel in the pixel section 803, and a signalline driving circuit 805 for supplying video signals to the selectedpixel. Also, a print substrate 806 is provided with a controller 801 anda power supply circuit 802. Various signals and power supply voltageoutput from the controller 801 or a power supply circuit 802 aresupplied to the pixel section 803, the scanning line driving circuit 804and the signal line driving circuit 805 of the EL panel 800 via FPC 807.

The power supply voltage and various signals to the print substrate 806are supplied via an interface (I/F) section 808 on which a plurality ofinput terminals are disposed. In this embodiment, the print substrate806 is mounted on the EL panel 800 using FPC, but the invention is notlimited to this particular construction. The controller 801 and thepower supply circuit 802 may be mounted directly on the EL panel 800using COG (Chip on Glass) technique. In the print substrate 806, noisesmay be introduced in the power supply voltage or the signals due to thecapacity formed in the wirings or the resistance of the wirings itself,which may prevent sharp rising edge of a signal. In order to avoid thisproblem, the print substrate 806 may be provided with elements such as acapacitor or a buffer, to prevent noises on the power supply voltage orsignals, and to keep sharp rising edge of the signal.

FIG. 23B is a block diagram which shows a construction of the printsubstrate 806. The various signals and the power supply voltage suppliedto the interface 808 are supplied to the controller 801 and the powersupply voltage 802. The controller 801 has an A/D converter 809, a PLL(phase locked loop) 810, a control signal generator 811 and SRAMs(Static Random Access Memory) 812 and 813. Although this embodiment usesSRAMs, SDRAMs or DRAMs (Dynamic Random Access Memory, provided that itcan read/write data at high speed) may be used as well.

The video signals supplied via the interface 808 are converted fromparallel form to serial form by the A/D converter 809, and input intothe control signal generator 811, as video signals each of whichcorresponds to R, G, B colors, respectively. Based on the signalssupplied via the interface 808, the A/D converter 809 generates Hsyncsignals, Vsync signals, clock signal CLKs, and volts alternating current[VAC], all of which are input into the control signal generator 811.

The phase locked loop 810 is able to make the phases of the frequenciesof the various signals supplied via the interface 808 to be matched tothat of the operating frequency of the control signal generator 811. Theoperating frequency of the control signal generator 811 is not alwayssame as the frequency of the various signals supplied via the interface808, so that the phase locked loop 810 adjusts the operating frequencyof the control signal generator 811 to make the frequency synchronizedwith that of the signals. The video signal which is input into thecontrol signal generator 811 is temporarily written and stored in theSRAMs 812 and 813. From all of the video signal bits stored in the SRAM812, the control signal generator 811 reads the video signalcorresponding to the all pixels by one bit at a time, and supplies thebit to the signal line driving circuit 805 of the EL panel 800.

The control signal generator 811 supplies information related to theperiod during which the light emitting element emits light for each bit,to the scanning line driving circuit 804 of the EL panel 800. The powersupply circuit 802 supplies the predetermined power supply voltage t6the signal line driving circuit 805, the scanning line driving circuit804 and the pixel section 803, of the EL panel 800.

FIG. 22 shows examples of electronic apparatuses in which the above ELmodule may be incorporated.

FIG. 22A is an example of a television receiver in which the EL moduleis incorporated, comprising a casing 3001, a support 3002 and a displayunit 3003. The TFT substrate manufactured according to the invention isadopted in the display unit 3003 to complete the television receiver.

FIG. 22B is an example of a video camera in which the EL module isincorporated, comprising a body 3011, a display unit 3012, a sound input3013, an operating switch 3014, a battery 3015 and an image receivingsection 3016. The TFT substrate manufactured according to the inventionis adopted in the display unit 3012 to complete the video camera.

FIG. 22C is an example of a notebook-type personal computer in which theEL module is incorporated, comprising a body 3021, a casing 3022, adisplay unit 3023 and a keyboard 3024. The TFT substrate manufacturedaccording to the invention is adopted in the display unit 3023 tocomplete the personal computer.

FIG. 22D is an example of PDA (Personal Digital Assistant) in which theEL module is incorporated, comprising a body 3031, a stylus 3032, adisplay unit 3033, an operating button 3034 and an external interface3035. The TFT substrate manufactured according to the invention isadopted in the display unit 3033 to complete the PDA.

FIG. 22E is an example of an car audio system in which the EL module isincorporated, comprising a body 3041, a display unit 3042 and operatingswitches 3043 and 3044. The TFT substrate manufactured according to theinvention is adopted in the unit display 3042 to complete the car audiosystem.

FIG. 22F is an example of a digital camera in which the EL module isincorporated, comprising a body 3051, a display unit (A) 3052, aneyepiece 3053, an operating switch 3054, a display unit (B) 3055 and abattery 3056. The TFT substrates manufactured according to the inventionare adopted to the display units (A) 3052 and (B) 3055 to complete thedigital camera.

FIG. 22G is an example of a mobile telephone in which the El module isincorporated, comprising a body 3061, a voice output section 3062, avoice input section 3063, a display unit 3064, an operating switch 3065and an antenna 3066. The TFT substrate manufactured according to theinvention is adopted to the display unit 3064 to complete the mobiletelephone.

The application of the invention is not limited to the apparatuses shownin this figure. Instead, it can be adopted in a variety of electronics.

According to the invention, the semiconductor film, the gate insulationfilm and the gate electrode, which are the main components of a TFT, aresurrounded by inorganic insulation materials over their upper surfacesand under their lower surfaces to prevent contamination by alkali metalsand organic materials. The inorganic insulation material is selectedfrom a group consisting of silicon nitride, silicon oxynitride, aluminumoxynitride, aluminum oxide and aluminum nitride. The organic lightemitting element contains alkali metal in its part, and surrounded byinorganic insulation material to realize a construction which canprevent penetration of oxygen or moisture from external world. Theinorganic insulation material is selected from a group consisting ofsilicon nitride, silicon oxynitride, aluminum oxynitride, aluminumnitride and DLC. This construction can improve the reliability of thelight emitting apparatus.

1. A light emitting device comprising: a light emitting elementincluding an organic compound layer containing light emitting materialbetween a cathode layer and an anode layer over an organic resinsubstrate; and a sealing plate made of an organic resin over the lightemitting element, wherein an upper surface, a lower surface and a sidesurface of the light emitting element is surrounded with inorganicinsulation layers, and wherein the cathode layer, the anode layer, andthe layer containing light emitting material is in contact with theinorganic insulation layers.
 2. The light emitting device according toclaim 1, wherein the organic resin substrate comprises aramid.
 3. Thelight emitting device according to claim 1, wherein the sealing platehas 30 to 120 μm thickness.
 4. The light emitting device according toclaim 1, wherein the inorganic insulation layers comprise a materialselected from the group consisting of silicon nitride and aluminumnitride.
 5. The light emitting device according to claim 1, wherein thelight emitting device is incorporated in a mobile telephone.
 6. A lightemitting device comprising: a transistor comprising a source region anda drain region over an organic resin substrate; a light emitting elementincluding an organic compound layer containing light emitting materialbetween a cathode layer and an anode layer over the organic resinsubstrate; and a sealing plate made of an organic resin over the lightemitting element, wherein the anode layer is electrically connected toone of the source region and the drain region, wherein an upper surface,a lower surface and a side surface of the light emitting element issurrounded with inorganic insulation layers, and wherein the cathodelayer, the anode layer, and the layer containing light emitting materialis in contact with the inorganic insulation layers.
 7. The lightemitting device according to claim 6, wherein the organic resinsubstrate comprises aramid.
 8. The light emitting device according toclaim 6, wherein the sealing plate has 30 to 120 μm thickness.
 9. Thelight emitting device according to claim 6, wherein the inorganicinsulation layers comprise a material selected from the group consistingof silicon nitride and aluminum nitride.
 10. The light emitting deviceaccording to claim 6, wherein the light emitting device is incorporatedin a mobile telephone.
 11. A light emitting device comprising: a pixelsection having a light emitting element including an organic compoundlayer containing light emitting material between a cathode layer and ananode layer over an organic resin substrate; a driving circuit sectionhaving a seal pattern; a sealing plate which is made of an organic resinand in contact with the seal pattern, over the light emitting element,wherein an upper surface, a lower surface and a side surface of thelight emitting element is surrounded with inorganic insulation layers,wherein the cathode layer, the anode layer, and the layer containinglight emitting material is in contact with the inorganic insulationlayers, and wherein the seal pattern is separated from the cathode. 12.The light emitting device according to claim 11, wherein the organicresin substrate comprises aramid.
 13. The light emitting deviceaccording to claim 11, wherein the sealing plate has 30 to 120 μmthickness.
 14. The light emitting device according to claim 1, whereinthe inorganic insulation layers comprise a material selected from thegroup consisting of silicon nitride and aluminum nitride.
 15. The lightemitting device according to claim 11, wherein the light emitting deviceis incorporated in a mobile telephone.
 16. A light emitting devicecomprising: a transistor comprising a source region and a drain regionover an organic resin substrate; a pixel section having a light emittingelement including an organic compound layer containing light emittingmaterial between a cathode layer and an anode layer over the organicresin substrate; a driving circuit section having a seal pattern; and asealing plate which is made of an organic resin and in contact with theseal pattern over the light emitting element, wherein the anode layer iselectrically connected to one of the source region and the drain region,wherein an upper surface, a lower surface and a side surface of thelight emitting element is surrounded with inorganic insulation layers,wherein the cathode layer, the anode layer, and the layer containinglight emitting material is in contact with the inorganic insulationlayers, and wherein the seal pattern is separated from the cathode. 17.The light emitting device according to claim 16, wherein the organicresin substrate comprises aramid.
 18. The light emitting deviceaccording to claim 16, wherein the sealing plate has 30 to 120 μmthickness.
 19. The light emitting device according to claim 16, whereinthe inorganic insulation layers comprise a material selected from thegroup consisting of silicon nitride and aluminum nitride.
 20. The lightemitting device according to claim 16, wherein the light emitting deviceis incorporated in a mobile telephone.